OTTAWA -- Justin Trudeau is standing by a senior government official who suggested factions within the Indian government were involved in sabotaging the prime minister's visit to India last week.

During his first question period since arriving back in Canada, opposition MPs grilled the prime minister Tuesday about invitations issued to Jaspal Atwal -- a B.C. Sikh convicted of attempting to assassinate an Indian cabinet minister in 1986 -- to attend two events with the prime minister in India.

In a background briefing arranged by the Prime Minister's Office, a government official last week suggested that Atwal's presence was arranged by factions within the Indian government who want to prevent Prime Minister Narendra Modi from getting too cosy with a foreign government they believe is not committed to a united India.

Justin Trudeau just made an incredibly serious charge against the Indian government – which has real implications for Canada’s foreign relations and national security. He needs to provide proof of this immediately. https://t.co/Vlpx43q2KO

Conservatives identified the official as Trudeau's national security adviser, Daniel Jean, and they pressed Trudeau to say whether he agrees with Jean's "conspiracy theory."

"A senior security official made these allegations. Does the prime minister agree or disavow those allegations?" asked Opposition Leader Andrew Scheer.

Prime Minister Justin Trudeau stands during question period in the House of Commons on Parliament Hill in Ottawa on Tuesday, Feb. 27, 2018. THE CANADIAN PRESS/Sean Kilpatrick

Trudeau defended the official as a member of the professional, non-partisan public service which provides quality advice.

He accused the previous Conservative government of using the public service for partisan ends, saying "they torqued the public service every possible way they could.

"And they do not understand that our professional, non-partisan public service does high quality work. And when one of our top diplomats and security officials says something to Canadians, it's because they know it to be true."

Conservative MPs pressed Trudeau to provide evidence to back the assertion, but it was left to Public Safety Minister Ralph Goodale to field those questions.

"Before our prime minister destroys our relationship with our ally, the government and country of India, will he please tell this house what proof he has of that allegation?" asked Tory MP Candice Bergen.

Goodale said Bergen was providing "her interpretation of events" and said "her insinuations and her accusations are false."

Atwal was convicted of attempting to kill Indian cabinet minister Malkiat Singh Sidhu on Vancouver Island in 1986.

He was also charged, but not convicted, in connection with a 1985 attack on Ujjal Dosanjh, a staunch opponent of the Sikh separatist movement, who later became B.C. premier and a federal Liberal cabinet minister.

A photo is making the rounds of Prime Minister Justin Trudeau's wife, Sophie Gregoire, at a function in India where she was snapped next to Jaspal Atwal. (Handout)

Trudeau's office says Atwal's invitation to a party in New Delhi was revoked as soon as his name was discovered on the guest list. However, Atwal showed up at a reception earlier in the week in Mumbai and was photographed with Sophie Gregoire Trudeau, the prime minister's wife.

British Columbia MP Randeep Sarai, one of several Liberal MPs in India with Trudeau, has taken responsibility for inviting Atwal and acknowledged he should have used better judgment.